Locking-bar motor-frame assembly



Aug. 24, 1948. A. E. Goobwm ETAL 2,447,545 I LOCKING-BAR MOTOR FRAMEASSEMBLY Filed Aug. 15, 1946 Fig.l.

Fig.2.

5 A ie WITNESSES:

. A m EE%VENJORS &

r ur o0 wan fiw I BOORLUdWiQ.

ATTORNEY Patented Aug. 24, 1948 LOCKING-BAR MOTOR-FRAME ASSEMBLY ArthurE. Goodwin, Eggertsville, N. Y., and Leon R. Ludwig, Pittsburgh, Pa..,asslgnors to Westinghouse Electric Corporation, East Pittsburgh. Pa., acorporation of Pennsylvania Application August 15, 1946, Serial No.690,629

2 Claims.

Our invention relates to electric motors, and it has more particularrelation to redesigned line of induction motors, which have beenrestudied, from all angles, including cost-reduction, for the purposeofascertaining what departures are possible, from standard or conventionalpractices, resulting in a saving or advantage of any kind, either acost-saving, a size-reduction, or the like.

The principal object of our invention is to provide a stator-coreassembly which locks together, with looking bars, fitting indifferent-sized notches in the stator-laminations and in the end-plateswhich retain the stator-laminations under compression, so that the wholefits together, like a Chinese puzzle, thus providing a constructionwhich is much more convenient and less expensive, and in many respectsmore desirable, than riveting, welding, and other forms of connection.

Heretofore, one ofthe known ways of assembling stator punchings, was toinsert them axially into stacking-rods or bars, or into the inside ofstator frame-ring. However, such constructions have necessitated havingsuch a loose fit, between the outer peripheries of the punchings and themembers on which the punchings were stacked, that a good thermaljunction was not made. This loose fit was necessitated by the fact thatthe punchings had to be loose enough to be movable axially, in theprocess of stacking. Other designs have been known, in which the statorpunchings were completely assembled together, and permanently held intheir assembled or compressed condition, before being pressed into astator frame-ring, and this design has at times utilized a sufficientlytight fit, between the outer periphery of the stator punchings orlaminations, and the inside of the stator frame-ring, so as to effect aready heat-exchange between the stator laminations and the frame-ring.

Our present invention relates to the second type of punchings, andparticularly to a novel locking-bar method of assembly thereof.

With the foregoing and other objects in view, our invention consists inthe structures, combinations, systems, methods and parts, hereinafterdescribed and claimed, and illustrated in the accompanying drawing,wherein:

Figure 1 is a longitudinal sectional view of a squirrel-cageinduction-motor embodying our invention by way of example.

Fig. 2 is a longitudinal sectional view of the stator frame and coreparts, without the statorwinding, the section-plane being indicated bythe broken line IIII in Fig. 3,

in bearings 8 carried by two end-brackets 9.

The stator-core assembly 5 consists of a coreproper, which is made up ofa stack of statorlaminations IO which carry stator windings II, disposedin slots 12. Two end-plates l3 are provided, one at each end of thestack of statorlaminations l0.

, In the particular stator-core assembly which is shown in our drawing,the stator-laminations ID are of approximately somewhat square shape,with the corners rounded off, so as to make a tight fit, at H, with theinside of the frame-ring 4, requiring th punchings to be forceablypressed into the frame ring, in the final assembly, so as to make a goodthermal connection at these points,

'the remainder of the outer periphery of the punchings being spaced fromthe inside of the frame-ring 4, so as to provide axially extendingventilating-spaces I5. The outer peripheries of the end-plates iii aresimilarly shaped, except that the outer diameter of th circular cornersof the end-plates is not quite as large as the corresponding outerdiameter of the punchings, so as not to interfere with the good thermalfit of the punchings, within the frame-ring 4. In the final assembly,the end-plates i3 may be welded in place, within the frame-ring 4, asindicated at 16 in Fig. 3.

' At the four corners of the punchings [0, slots I! are provided, whichopenperipherally, as shown in Fig. 3. The end-plates l3 are similarlyprovided with slots l8, except that the slots l8 of the end-plates aresomewhat narrower and smaller than the slots I! of the punchings orlaminations.

In the assembly of the stator-core It), with its two end-plates I3,before the stator-winding II is added, and before the core-assembly ispressed into the frame-ring 4, the core and end-plates are assembledtogether under pressure, and while they are still held under theadequate pressure, four locking-bars l9 are dropped into the slots i1and I8, at the four corners of the assembly. These locking bars H! areround rods, having a diameter which just fl-t within the slots I! whichare provided in the corners or the punchings or laminations l0. Eachlocking-bar i8 is provided, near each oi? its ends, with a groove 2|, orreduced-diameter portion, which fits within the smaller slots l8 whichare provided in the tour corners of the end-plates. The parts thus fittogether like a Chinese puzzle, so that. when the holding pressure isreleased from the stack of laminations and end-plates, the whole is heldtightly together in assembled position.

The stator-core assembly is now in condition for the addition or thestator-windings II, and when these have been added, the whole.coreassembly can then be pressed into the stator frame-ring 4, andwelded in position at l8. as shown in Fig. 3.

The ends oi! the. locking-bars l9 may be predrilled at 22, toaccommodate the bracket-bolts 23 which secure the brackets 8 to theframe.

Other features of our invention, which may be shown in the drawing,constitute the subjectmatter of a contemporaneously filed application ofLeon R. Ludwig, Theodore C. Fockler, William H. Formhals, and Howard T.Walton, Serial No. 690,628, filed August 15, 1946, relating to comvertible-Irame motors having interchangeable parts.

We claim as our invention:

1. A dynamo-electric machine characterized by a stator constructioncomprising a name-ring, a stator-core comprising a rigidly held stack ofstator-laminations fitting within the inside oi! the frame-ring, eachlamination having a slot,

locking-bars, each locking-bar having a crosssectional size fitting inthe peripheral lamination slots, and having two grooves-fitting in theperipheral slot of the two end-plates, a statorwinding carried bythe-stator-core, and structural means for securing the stator-coreassembly within the frame-ring.

2. A dynamo-electric machine characterized by a stator constructioncomprising a frame-ring, a stator-core comprising a rigidly held stackof stator-laminations fitting, at a plurality of spaced points about theouter periphery of the statorlaminations, within the inside of theframe-ring,

, the stator-laminations being spaced from the inopening into its outerperiphery, at each of a plurality oi frame-ring-fltting points, twoend-plates for pressing the stator-laminations together, each end-platehaving a slot, opening into its outer periphery, at points correspondingto the corresponding slots in the stator-laminatlons, the

Y peripheral end-plate slots being narrower than the peripherallamination slots, a plurality of side of the frame-ring at otherperipheralpolnts, each lamination having a slot, opening into its outerperiphery. at each of a plurality of framering-fitting points, twoend-plates for pressing the stator-laminations together, each end-platehaving a slot, opening into its outer periphery, at points correspondingto the corresponding slots in the stator-laminations, the peripheralendplate slots being narrower than the peripheral lamination slots, aplurality of locking-bars, each locking-bar having a cross-sectionalsize fittin in the peripheral lamination slots, and having two groovesfitting in the peripheral slots oi the two end-plates, a stator-windingcarried by the stator-core, and structural means for securing thestator-core assembly within the frame-ring.

' ARTHUR E. GOODWIN.

LEON R. LUDWIG.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS

